Fuel additives for treating internal deposits of fuel injectors

ABSTRACT

A method cleaning up internal components of a fuel injector for a diesel engine. The method includes operating a fuel injected diesel engine on a fuel composition that includes a major amount of diesel fuel and from about 5 to about 500 ppm by weight of a reaction product derived from (a) a hydrocarbyl substituted dicarboxylic acid, anhydride, or ester and (b) an amine compound or salt thereof of the formula 
                         
wherein R is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms, and R 1  is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms. The reaction product is characterized by a particular FTIR spectrum.

RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.13/240,233, filed Sep. 22, 2011, now U.S. Pat. No. 8,758,456.

TECHNICAL FIELD

The disclosure is directed to certain diesel fuel additives and tomethod for cleaning and/or preventing internal deposits in injectors fordiesel fuel operated engines. In particular the disclosure is directedto methods that are effective against internal deposits in injectors forengines operating on ultra low sulfur diesel fuels.

BACKGROUND AND SUMMARY

Recent changes in diesel fuels and diesel fuel additives have resultedin new injector performance concerns with deposits, including a new typeof deposit not experienced with older diesel fuel formulations. Theinjector performance concerns run across all segments; on-road fleets,mining equipment, farming equipment, railroad and inland marine engines.

Vehicle operators, fuel marketers, and engine manufacturers are nowseeing deposits forming on the internal parts of fuel injectors. If leftuntreated, these deposits may lead to significant power loss, reducedfuel economy, and, in extreme cases, increased downtime and highermaintenance costs due to premature replacement of “stuck injectors.” Thenew deposits are believed to be a result of certain common corrosioninhibitors, biofuel components and acidic friction modifier, or othercarboxylic components used in the fuel reacting with trace amounts oftransition metals, alkali metal and alkaline earth metals causing saltsthat are less soluble in ultra low sulfur diesel (ULSD) fuels than inthe higher sulfur fuels of the past. When such salts are present in fuelthat is used in a High Pressure Common Rail (HPCR) engine design, thesalts may tend to deposit in the very tight tolerance areas of theinjectors. Such deposits may lead to poor fuel injection, which in turnmay lead to lost power, lost fuel economy, rough running engines, andeventually excessive vehicle downtime and maintenance expense.

ULSD now represents about 79% of all distillate fuel supplied in theUnited States. Also, the Renewable Fuel Standard minimum for biodieselwas raised to 1 billion gallons in 2012. There are indications that theamount of biodiesel required to be used in fuel will be even higher inthe future. Accordingly, the changing fuel slate continues to movetoward more ULSD (with less solubility for salts that can form) and morebiodiesel in the marketplace (another potential source of depositcausing materials in the fuel system).

In accordance with the disclosure, exemplary embodiments provide amethod cleaning up internal components of a fuel injector for a dieselengine. The method includes operating a fuel injected diesel engine on afuel composition that contains a major amount of diesel fuel having asulfur content of 50 ppm by weight or less and from about 5 to about 500ppm by weight of a reaction product derived from (a) a hydrocarbylsubstituted dicarboxylic acid, anhydride, or ester and (b) an aminecompound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms. The reactionproduct is characterized by an FTIR spectrum having a peak intensity ina region of from about 1630 cm⁻¹ to about 1645 cm⁻¹ that ranges fromabout 5 to about 45% of peak intensities of other peaks in a region offrom about 1500 cm⁻¹ to about 1800 cm⁻¹.

Another embodiment of the disclosure provides a method for reducing anamount of salt deposits on internal components of a fuel injector for afuel injected diesel engine. The method includes operating the dieselengine on a fuel composition that contains a major amount of fuel and aminor amount of a reaction product derived from (a) a hydrocarbylsubstituted dicarboxylic acid, anhydride, or ester and (b) an aminecompound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms. The reactionproduct contains less than one equivalent of an amino triazole group permolecule of reaction product.

A further embodiment of the disclosure provides a method for preventingplugging of a fuel filter for fuel injectors of a fuel injected dieselengine. The method includes providing a major amount of fuel and a minoramount of a reaction product derived from (a) a hydrocarbyl substituteddicarboxylic acid, anhydride, or ester and (b) an amine compound or saltthereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms. The reactionproduct is characterized by an FTIR spectrum having a peak intensity ina region of from about 1630 cm⁻¹ to about 1645 cm⁻¹ that ranges fromabout 5 to about 45% of peak intensities of other peaks in a region offrom about 1500 cm⁻¹ to about 1800 cm⁻¹, and wherein the reactionproduct contains less than one equivalent of an amino triazole group permolecule of reaction product.

An advantage of the fuel additive described herein is that the additivemay not only reduce the amount of internal deposits forming on directand/or indirect diesel fuel injectors, but the additive may also beeffective to clean up dirty fuel injectors and may prevent the pluggingof fuel filters in the fuel supply to the fuel injectors.

Additional embodiments and advantages of the disclosure may be set forthin part in the detailed description which follows, and/or may be learnedby practice of the disclosure. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of thedisclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a portion of an FTIR spectrum of a prior art product.

FIG. 2 is a portion of an FTIR spectrum of a reaction product accordingto the disclosure.

FIG. 3 is a graphical representation of exhaust gas cylindertemperatures over time for a four cylinder diesel engine at thebeginning of a test for fuel additives.

FIG. 4 is a graphical representation of exhaust gas cylindertemperatures over time for a four cylinder diesel engine after eighthours of testing using no fuel detergent.

FIGS. 5 and 6 are graphical representations of exhaust gas cylindertemperatures over time for a four cylinder diesel engine usingconventional fuel detergents.

FIG. 7 is graphical representations of exhaust gas cylinder temperaturesover time for a four cylinder diesel engine using a fuel detergentaccording to an embodiment of the disclosure.

FIG. 8 is a graphical representation of exhaust gas cylindertemperatures over time for a four cylinder diesel engine at the end of adirty up test cycle.

FIG. 9 is a graphical representation of exhaust gas cylindertemperatures over time for a four cylinder diesel engine using a fueldetergent according to an embodiment of the disclosure to clean-up dirtyfuel injectors of FIG. 6.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The compositions of the present application may be used in a minoramount in a major amount of diesel fuel and may be made by reacting anamine compound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms with ahydrocarbyl substituted dicarboxylic acid, anhydride, or ester, whereinthe reaction product contains less than one equivalent of amino triazolegroup per molecule of reaction product. The reaction product ischaracterized by an FTIR spectrum having a peak intensity in a region offrom about 1630 cm⁻¹ to about 1645 cm-1 that ranges from about 5 toabout 45% of peak intensities of other peaks in a region of from about1500 cm⁻¹ to about 1800 cm⁻¹.

For comparison purposes, FIG. 1 shows an FTIR spectrum of a compoundmade with from about mole ratio of hydrocarbyl carbonyl to amine rangingfrom about 1:1 to about 1:2.5. The peak at about 1636 cm⁻¹ is believedto be an aminotriazole peak. By comparison, the reaction product madeaccording to the disclosed embodiments has an FTIR spectrum as shown inFIG. 2, wherein the peak intensity at about 1636 cm⁻¹ is substantiallysmaller than the peak intensity of other peaks in a region of from about1500 cm⁻¹ to about 1800 cm⁻¹. For example, the reaction productaccording to the disclosure has a peak intensity in the region of from1630 cm⁻¹ to about 1645 cm⁻¹ that ranges from about 5 to about 45% ofpeak intensities of other peaks in a region of from about 1500 cm⁻¹ toabout 1800 cm⁻¹. In other embodiments, the reaction product has acharacteristic peak intensity in the range of from 1630 cm⁻¹ to about1645 cm⁻¹ that is no more than 30%, for example no more than 25%, andtypically no more than 10% of the intensity of other peaks in the rangeof from about 1500 cm⁻¹ to about 1800 cm⁻¹.

As used herein, the term “hydrocarbyl group” or “hydrocarbyl” is used inits ordinary sense, which is well-known to those skilled in the art.Specifically, it refers to a group having a carbon atom directlyattached to the remainder of a molecule and having a predominantlyhydrocarbon character. Examples of hydrocarbyl groups include:

-   -   (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or        alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl)        substituents, and aromatic-, aliphatic-, and        alicyclic-substituted aromatic substituents, as well as cyclic        substituents wherein the ring is completed through another        portion of the molecule (e.g., two substituents together form an        alicyclic radical);    -   (2) substituted hydrocarbon substituents, that is, substituents        containing non-hydrocarbon groups which, in the context of the        description herein, do not alter the predominantly hydrocarbon        substituent (e.g., halo (especially chloro and fluoro), hydroxy,        alkoxy, mercapto, alkylmercapto, nitro, nitroso, amino,        alkylamino, and sulfoxy);    -   (3) hetero-substituents, that is, substituents which, while        having a predominantly hydrocarbon character, in the context of        this description, contain other than carbon in a ring or chain        otherwise composed of carbon atoms. Hetero-atoms include sulfur,        oxygen, nitrogen, and encompass substituents such as pyridyl,        furyl, thienyl, and imidazolyl. In general, no more than two, or        as a further example, no more than one, non-hydrocarbon        substituent will be present for every ten carbon atoms in the        hydrocarbyl group; in some embodiments, there will be no        non-hydrocarbon substituent in the hydrocarbyl group.

“Biorenewable fuels” and “biodiesel fuels” as used herein is understoodto mean any fuel which is derived from resources other than petroleum.Such resources include, but are not limited to, corn, maize, soybeansand other crops; grasses, such as switchgrass, miscanthus, and hybridgrasses; algae, seaweed, vegetable oils; natural fats; and mixturesthereof. In an aspect, the biorenewable fuel may include monohydroxyalcohols, such as those having from 1 to about 5 carbon atoms.Non-limiting examples of suitable monohydroxy alcohols include methanol,ethanol, propanol, n-butanol, isobutanol, t-butyl alcohol, amyl alcohol,and isoamyl alcohol.

As used herein, the term “major amount” is understood to mean an amountgreater than or equal to 50 wt. %, for example from about 80 to about 98wt. % relative to the total weight of the composition. Moreover, as usedherein, the term “minor amount” is understood to mean an amount lessthan 50 wt. % relative to the total weight of the composition.

As used herein, the term “salts or salt deposits” are understood to meantransition metal, alkali metal or alkaline earth metal carboxylates.

Amine Compound

Suitable amine compounds of the formula

may be chosen from guanidines and aminoguanidines or salts thereofwherein R and R¹ are as defined above. Accordingly, the amine compoundmay be chosen from the inorganic salts of guanidines, such as thehalide, carbonate, nitrate, phosphate, and orthophosphate salts ofguanidines. The term “guanidines” refers to guanidine and guanidinederivatives, such as aminoguanidine. In one embodiment, the guanidinecompound for the preparation of the additive is aminoguanidinebicarbonate. Aminoguanidine bicarbonates are readily obtainable fromcommercial sources, or can be prepared in a well-known manner.Hydrocarbyl Carbonyl Compound

The hydrocarbyl carbonyl reactant compound of the additive may be anysuitable compound having a hydrocarbyl moiety and a carbonyl moiety, andthat is capable of bonding with the amine compound to form the additivesof the disclosure. Non-limiting examples of suitable hydrocarbylcarbonyl compounds include, but are not limited to, hydrocarbylsubstituted succinic anhydrides, hydrocarbyl substituted succinic acids,and esters of hydrocarbyl substituted succinic acids.

In some aspects, the hydrocarbyl carbonyl compound may be a polyalkylenesuccinic anhydride reactant having the following formula:

wherein R² is a hydrocarbyl moiety, such as for example, a polyalkenylradical having a number average molecular weight of from about 100 toabout 5,000 daltons. For example, the number average molecular weight ofR² may range from about 200 to about 3,000 daltons, as measured by GPC.Unless indicated otherwise, molecular weights in the presentspecification are number average molecular weights.

In the above formula, the R² hydrocarbyl moiety may comprise one or morepolymer units chosen from linear or branched alkenyl units. In someaspects, the alkenyl units may have from about 2 to about 10 carbonatoms. For example, the polyalkenyl radical may comprise one or morelinear or branched polymer units chosen from ethylene radicals,propylene radicals, butylene radicals, pentene radicals, hexeneradicals, octene radicals and decene radicals. In some aspects, the R²polyalkenyl radical may be in the form of, for example, a homopolymer,copolymer or terpolymer. In one aspect, the polyalkenyl radical isisobutylene. For example, the polyalkenyl radical may be a homopolymerof polyisobutylene comprising from about 10 to about 60 isobutylenegroups, such as from about 20 to about 30 isobutylene groups. Thepolyalkenyl compounds used to form the R² polyalkenyl radicals may beformed by any suitable methods, such as by conventional catalyticoligomerization of alkenes.

In an additional aspect, the hydrocarbyl moiety R² may be derived from alinear alpha olefin or an acid-isomerized alpha olefin made by theoligomerization of ethylene by methods well known in the art. Thesehydrocarbyl moieties can range from about 8 carbon atoms to over 40carbon atoms. For example, alkenyl moieties of this type may be derivedfrom a linear C₁₈ or a mixture of C₂₀₋₂₄ alpha olefins or fromacid-isomerized C₁₆ alpha olefins.

In some aspects, high reactivity polyisobutenes having relatively highproportions of polymer molecules with a terminal vinylidene group may beused to form the R² group. In one example, at least about 60%, such asabout 70% to about 90%, of the polyisobutenes comprise terminal olefinicdouble bonds. There is a general trend in the industry to convert tohigh reactivity polyisobutenes, and well known high reactivitypolyisobutenes are disclosed, for example, in U.S. Pat. No. 4,152,499,the disclosure of which is herein incorporated by reference in itsentirety.

Specific examples of hydrocarbyl carbonyl compounds include suchcompounds as dodecenylsuccinic anhydrides, C₁₆₋₁₈ alkenyl succinicanhydride, and polyisobutenyl succinic anhydride (PIBSA), and acid andester compounds derived therefrom. In some embodiments, the PIBSA mayhave a polyisobutylene portion with a vinylidene content ranging fromabout 4% to greater than about 90%. In some embodiments, the molar ratioof the number of carbonyl groups to the number of hydrocarbyl moietiesin the hydrocarbyl carbonyl compound may range from about 0.5:1 to about5:1.

In some aspects, approximately one mole of maleic anhydride may bereacted per mole of polyalkylene, such that the resulting polyalkenylsuccinic anhydride has about 0.8 to about 1 succinic anhydride group perpolyalkylene substituent. In other aspects, the molar ratio of succinicanhydride groups to alkylene groups may range from about 0.5 to about3.5, such as from about 1 to about 1.1.

The hydrocarbyl carbonyl compounds may be made using any suitablemethod. Methods for forming hydrocarbyl carbonyl compounds are wellknown in the art. One example of a known method for forming ahydrocarbyl carbonyl compound comprises blending a polyolefin and maleicanhydride. The polyolefin and maleic anhydride reactants are heated totemperatures of, for example, about 150° C. to about 250° C.,optionally, with the use of a catalyst, such as chlorine or peroxide.Another exemplary method of making the polyalkylene succinic anhydridesis described in U.S. Pat. No. 4,234,435, which is incorporated herein byreference in its entirety.

The hydrocarbyl carbonyl and amine compounds described above may bemixed together under suitable conditions to provide the desired reactionproduct of the present disclosure. In one aspect of the presentdisclosure, the reactant compounds may be mixed together in a mole ratioof hydrocarbyl carbonyl compound to amine ranging from about 1:0.5 toabout 1:1.5. For example, the mole ratio of the reactants may range fromabout 1:0.5 to about 1:0.95.

Suitable reaction temperatures may range from about 130° C. to less thanabout 200° C. at atmospheric pressure. For example, reactiontemperatures may range from about 140° C. to about 160° C. Any suitablereaction pressures may be used, such as, including subatmosphericpressures or superatmospheric pressures. However, the range oftemperatures may be different from those listed where the reaction iscarried out at other than atmospheric pressure. The reaction may becarried out for a period of time within the range of about 1 hour toabout 8 hours, preferably, within the range of about 2 hours to about 6hours.

In some aspects of the present application, the dispersant products ofthis application may be used in combination with a diesel fuel solublecarrier. Such carriers may be of various types, such as liquids orsolids, e.g., waxes. Examples of liquid carriers include, but are notlimited to, mineral oil and oxygenates, such as liquid polyalkoxylatedethers (also known as polyalkylene glycols or polyalkylene ethers),liquid polyalkoxylated phenols, liquid polyalkoxylated esters, liquidpolyalkoxylated amines, and mixtures thereof. Examples of the oxygenatecarriers may be found in U.S. Pat. No. 5,752,989, issued May 19, 1998 toHenly et. al., the description of which carriers is herein incorporatedby reference in its entirety. Additional examples of oxygenate carriersinclude alkyl-substituted aryl polyalkoxylates described in U.S. PatentPublication No. 2003/0131527, published Jul. 17, 2003 to Colucci et.al., the description of which is herein incorporated by reference in itsentirety.

In other aspects, compositions of the present application may notcontain a carrier. For example, some compositions of the presentapplication may not contain mineral oil or oxygenates, such as thoseoxygenates described above.

One or more additional optional compounds may be present in the fuelcompositions of the disclosed embodiments. For example, the fuels maycontain conventional quantities of cetane improvers, corrosioninhibitors, cold flow improvers (CFPP additive), pour point depressants,detergents, solvents, demulsifiers, lubricity additives, frictionmodifiers, amine stabilizers, combustion improvers, dispersants,antioxidants, heat stabilizers, conductivity improvers, metaldeactivators, marker dyes, organic nitrate ignition accelerators,cyclomatic manganese tricarbonyl compounds, and the like. In someaspects, the compositions described herein may contain about 10 weightpercent or less, or in other aspects, about 5 weight percent or less,based on the total weight of the additive concentrate, of one or more ofthe above additives. Similarly, the fuels may contain suitable amountsof conventional fuel blending components such as methanol, ethanol,dialkyl ethers, and the like.

In some aspects of the disclosed embodiments, organic nitrate ignitionaccelerators that include aliphatic or cycloaliphatic nitrates in whichthe aliphatic or cycloaliphatic group is saturated, and that contain upto about 12 carbons may be used. Examples of organic nitrate ignitionaccelerators that may be used are methyl nitrate, ethyl nitrate, propylnitrate, isopropyl nitrate, allyl nitrate, butyl nitrate, isobutylnitrate, sec-butyl nitrate, tert-butyl nitrate, amyl nitrate, isoamylnitrate, 2-amyl nitrate, 3-amyl nitrate, hexyl nitrate, heptyl nitrate,2-heptyl nitrate, octyl nitrate, isooctyl nitrate, 2-ethylhexyl nitrate,nonyl nitrate, decyl nitrate, undecyl nitrate, dodecyl nitrate,cyclopentyl nitrate, cyclohexyl nitrate, methylcyclohexyl nitrate,cyclododecyl nitrate, 2-ethoxyethyl nitrate, 2-(2-ethoxyethoxy)ethylnitrate, tetrahydrofuranyl nitrate, and the like. Mixtures of suchmaterials may also be used.

Examples of suitable optional metal deactivators useful in thecompositions of the present application are disclosed in U.S. Pat. No.4,482,357, issued Nov. 13, 1984, the disclosure of which is hereinincorporated by reference in its entirety. Such metal deactivatorsinclude, for example, salicylidene-o-aminophenol, disalicylideneethylenediamine, disalicylidene propylenediamine, andN,N′-disalicylidene-1,2-diaminopropane.

Suitable optional cyclomatic manganese tricarbonyl compounds which maybe employed in the compositions of the present application include, forexample, cyclopentadienyl manganese tricarbonyl, methylcyclopentadienylmanganese tricarbonyl, indenyl manganese tricarbonyl, andethylcyclopentadienyl manganese tricarbonyl. Yet other examples ofsuitable cyclomatic manganese tricarbonyl compounds are disclosed inU.S. Pat. No. 5,575,823, issued Nov. 19, 1996, and U.S. Pat. No.3,015,668, issued Jan. 2, 1962, both of which disclosures are hereinincorporated by reference in their entirety.

When formulating the fuel compositions of this application, theadditives may be employed in amounts sufficient to reduce or inhibitdeposit formation in a diesel engine. In some aspects, the fuels maycontain minor amounts of the above described reaction product thatcontrols or reduces the formation of engine deposits, for exampleinjector deposits in diesel engines. For example, the diesel fuels ofthis application may contain, on an active ingredient basis, an amountof the reaction product in the range of about 5 mg to about 500 mg ofreaction product per Kg of fuel, such as in the range of about 20 mg toabout 120 mg of reaction product per Kg of fuel. In aspects, where acarrier is employed, the fuel compositions may contain, on an activeingredients basis, an amount of the carrier in the range of about 1 mgto about 100 mg of carrier per Kg of fuel, such as about 5 mg to about50 mg of carrier per Kg of fuel. The active ingredient basis excludesthe weight of (i) unreacted components such as polyalkylene compoundsassociated with and remaining in the product as produced and used, and(ii) solvent(s), if any, used in the manufacture of the reaction producteither during or after its formation but before addition of a carrier,if a carrier is employed.

The additives of the present application, including the reaction productdescribed above, and optional additives used in formulating the fuels ofthis invention may be blended into the base diesel fuel individually orin various sub-combinations. In some embodiments, the additivecomponents of the present application may be blended into the dieselfuel concurrently using an additive concentrate, as this takes advantageof the mutual compatibility and convenience afforded by the combinationof ingredients when in the form of an additive concentrate. Also, use ofa concentrate may reduce blending time and lessen the possibility ofblending errors.

The diesel fuels of the present application may be applicable to theoperation of both stationary diesel engines (e.g., engines used inelectrical power generation installations, in pumping stations, etc.)and ambulatory diesel engines (e.g., engines used as prime movers inautomobiles, trucks, road-grading equipment, military vehicles, etc.).For example, the fuels may include any and all middle distillate fuels,diesel fuels, biorenewable fuels, biodiesel fuel, gas-to-liquid (GTL)fuels, jet fuel, alcohols, ethers, kerosene, low sulfur fuels, syntheticfuels, such as Fischer-Tropsch fuels, liquid petroleum gas, bunker oils,coal to liquid (CTL) fuels, biomass to liquid (BTL) fuels, highasphaltene fuels, fuels derived from coal (natural, cleaned, andpetcoke), genetically engineered biofuels and crops and extractstherefrom, and natural gas. “Biorenewable fuels” as used herein isunderstood to mean any fuel which is derived from resources other thanpetroleum. Such resources include, but are not limited to, corn, maize,soybeans and other crops; grasses, such as switchgrass, miscanthus, andhybrid grasses; algae, seaweed, vegetable oils; natural fats; andmixtures thereof. In an aspect, the biorenewable fuel can comprisemonohydroxy alcohols, such as those comprising from 1 to about 5 carbonatoms. Non-limiting examples of suitable monohydroxy alcohols includemethanol, ethanol, propanol, n-butanol, isobutanol, t-butyl alcohol,amyl alcohol, and isoamyl alcohol.

Accordingly, aspects of the present application are directed to methodsfor reducing the amount of injector deposits of a diesel engine havingat least one combustion chamber and one or more direct fuel injectors influid connection with the combustion chamber. In another aspect, theimprovements may also be observed in indirect diesel fuel injectors. Insome aspects, the methods comprise injecting a hydrocarbon-basedcompression ignition fuel comprising the reaction product additive ofthe present disclosure, through the injectors of the diesel engine intothe combustion chamber, and igniting the compression ignition fuel. Insome aspects, the method may also comprise mixing into the diesel fuelat least one of the optional additional ingredients described above.

In one embodiment, the diesel fuels of the present application may beessentially free, such as devoid, of conventional succinimide dispersantcompounds. The term “essentially free” is defined for purposes of thisapplication to be concentrations having substantially no measurableeffect on injector cleanliness or deposit formation.

In yet other aspects of the present application, the fuel additive maybe free or substantially free of 1,2,4-triazoles. For example, thecompositions may be substantially free of triazoles of formula II,

wherein R⁴ and R⁵ are independently chosen from hydrogen and hydrocarbylgroups, with the proviso that at least one of R⁴ and R⁵ is not hydrogen.Examples of hydrocarbyl groups include C₂ to C₅₀ linear, branched orcyclic alkyl groups; C₂ to C₅₀ linear, branched or cyclic alkenylgroups; and substituted or unsubstituted aryl groups, such as phenylgroups, tolyl groups and xylyl groups.

EXAMPLES

The following examples are illustrative of exemplary embodiments of thedisclosure. In these examples as well as elsewhere in this application,all parts and percentages are by weight unless otherwise indicated. Itis intended that these examples are being presented for the purpose ofillustration only and are not intended to limit the scope of theinvention disclosed herein.

In the following examples, the effect the detergent additive had ondiesel fuel contaminated with carboxylate salts for high pressure commonrail diesel fuel systems was evaluated. An engine test was used todemonstrate the propensity of fuels to provoke fuel injector stickingand was also used to demonstrate the ability of certain fuel additivesto prevent or reduce the amount of internal deposit in the injectors. Anengine dynamometer test stand was used for the installation of thePeugeot DW10 diesel engine for running the injector sticking tests. Theengine was a 2.0 liter engine having four cylinders. Each combustionchamber had four valves and the fuel injectors were DI piezo injectorshave a Euro V classification.

The core protocol procedure consisted of running the engine through acycle for 8-hours and allowing the engine to soak (engine off) for aprescribed amount of time. The injector performance was thencharacterized by measuring the cylinder exhaust temperature for eachcylinder. A test was stopped and considered to have failed (one or moreinjectors sticking) if the exhaust temperature of any cylinder was morethan 65° C. above any other cylinder exhaust temperature at any point intime. A test was also considered to have failed if after allowing theengine to cool to ambient temperature, a cold start showed a temperaturedifference of 45° C. or more in cylinder exhaust temperatures. Stickingof the needle and thus failure could also be confirmed by disassemblingthe injector and subjectively determining the force required to removethe needle from the nozzle housing. Cleanliness tests were run forkeep-clean performance as well as clean-up performance.

Test preparation involved flushing the previous test's fuel from theengine prior to removing the injectors. The test injectors wereinspected, cleaned, and reinstalled in the engine. If new injectors wereselected, the new injectors were put through a 16-hour break-in cycle.Next, the engine was started using the desired test cycle program. Oncethe engine was warmed up, power was measured at 4000 RPM and full loadto check for full power restoration after cleaning the injectors. If thepower measurements were within specification, the test cycle wasinitiated. The following Table 1 provides a representation of the DW10sticking test cycle that was used to evaluate the fuel additivesaccording to the disclosure.

TABLE 1 One hour representation of DW10 sticking test cycle. DurationEngine speed Load Torque Boost air after Step (minutes) (rpm) (%) (Nm)Intercooler (° C.) 1 2 1750 20 62 45 2 7 3000 60 173 50 3 2 1750 20 6245 4 7 3500 80 212 50 5 2 1750 20 62 45 6 10 4000 100 * 50 7 2 1250 1025 43 8 7 3000 100 * 50 9 2 1250 10 25 43 10 10 2000 100 * 50 11 2 125010 25 43 12 7 4000 100 * 50

Example 1 Injector Sticking Engine Test

Diesel engine nozzle sticking tests were conducted using the PeugeotDW10 engine following the protocol of Table 1. For keep-clean testing,the engine was run with diesel fuel doped with metal carboxylate saltsand with the detergent additive indicated in the example. For clean-uptesting, the engine was first run with diesel fuel doped with metalcarboxylate salts without a detergent additive to establish a baselineof stuck fuel injectors. Next, the engine was run with the same fuelcontaining the detergent additive indicated. In all of the tests, thefuels tested contained 200 ppmv lubricity modifier and 1600 ppmv cetaneimprover, 20 ppmw of dodecyl succinic acid, 3 ppmw of NaOH, and 25 ppmwvof water. At the beginning of the test, no injector sticking wasindicated by a uniform exhaust gas temperature for all 4-cylinders asshown in FIG. 3. However, a cold start of the engine after 8 hoursshowed injector sticking as shown in FIG. 4. In all of the figures,curve A is cylinder 1, curve B is cylinder 2, curve C is cylinder 3 andcurve D is cylinder 4.

Comparative Example 2

In this example, a conventional succinimide dispersant additive wasadded to the fuel at a treat rate of 75 ppmw. FIG. 5 shows the injectorssticking after a 16 hour test with the fuel containing the conventionaldetergent.

Comparative Example 3

In this example a quaternary ammonium salt Diesel fuel additive packagewas added to the fuel at a treat rate of 75 ppmw. FIG. 6 shows theinjector sticking after a 7 hour test with this fuel.

Example 4

The detergent additive of the disclosure was added to the fuel at atreat rate of 75 ppmw. After a 16 hour test, FIG. 7 shows that none ofthe injectors were stuck. Physical inspection of the injectors uponcompletion of the test confirmed that none of the injectors were stuck.

Example 5

In this test, a base fuel containing the metal salts described above wasrun in the engine for 8 hours to dirty-up the fuel injectors. FIG. 8shows that after a cold start of the engine, the injectors were stuck.

Example 6

In this test, the ability of the detergent additive of the disclosure tothe clean-up dirty fuel injectors of FIG. 8 was demonstrated. In thisexample, 30 ppmw of the detergent additive of the disclosure wascombined with 120 ppmw of a conventional succinimide dispersant and thismixture was added to the fuel. FIG. 9 shows that after a 16 hour test,none of the injectors were stuck.

As indicated by the foregoing examples, fuel additives containingdetergent additive of the disclosure provides a significant reduction ininternal deposits in diesel fuel injectors when engines are operated onULSD fuels as compared to conventional fuel detergent additives and thatthe detergent additive was effective for cleaning up dirty fuelinjectors.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” include plural referents unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items

For the purposes' of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present disclosure. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

While particular embodiments have been described, alternatives,modifications, variations, improvements, and substantial equivalentsthat are or can be presently unforeseen can arise to applicants orothers skilled in the art. Accordingly, the appended claims as filed andas they can be amended are intended to embrace all such alternatives,modifications variations, improvements, and substantial equivalents.

What is claimed is:
 1. A method of cleaning up internal components of afuel injector for a diesel engine comprising operating the diesel engineon a fuel composition comprising a major amount of diesel fuel having asulfur content of 50 ppm by weight or less and from about 20 to about120 ppm by weight of a reaction product derived from (a) a hydrocarbylsubstituted dicarboxylic acid, anhydride, or ester, wherein thehydrocarbyl group is a polyisobutylene radical having a number averagemolecular weight ranging from about 200 to about 3000 daltons and (b) anamine compound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms, wherein thereaction product is made under conditions sufficient to provide that thereaction product contains less than one equivalent of an amino triazolegroup per molecule of reaction product, and wherein the reaction productis characterized by an FTIR spectrum having a peak intensity in a regionof from about 1630 cm⁻¹ to about 1645 cm⁻¹ that ranges from about 5 toabout 45% of peak intensities of other peaks in a region of from about1500 cm⁻¹ to about 1800 cm⁻¹.
 2. The method of claim 1, wherein a molarratio of (a) to (b) in the reaction product ranges from about 1:0.5 toabout 1:1.5.
 3. The method of claim 1, wherein the hydrocarbyldicarboxylic acid, anhydride or ester is chosen from hydrocarbylsubstituted succinic anhydrides, hydrocarbyl substituted succinic acids,and esters of hydrocarbyl substituted succinic acids.
 4. The method ofclaim 1, wherein the reaction product is effective to remove saltdeposits selected from the group consisting of transition metal, alkalimetal and alkaline earth metal carboxylates from the internal componentsof the fuel injector.
 5. The method of claim 1, wherein the fuelinjected diesel engine is a direct fuel injected diesel engine.
 6. Themethod of claim 1, wherein the amine is aminoguanidine bicarbonate.
 7. Amethod for reducing an amount of salt deposits on internal components ofa fuel injector for a fuel injected diesel engine comprising operatingthe diesel engine on a fuel composition comprising a major amount offuel and from about 20 to about 120 ppm by weight of a reaction productderived from (a) a polyisobutenyl hydrocarbyl substituted dicarboxylicacid, anhydride, or ester, wherein the polyisobutenyl group has a numberaverage molecular weight ranging from about 200 to about 3000 daltonsand (b) an amine compound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms, wherein thereaction product is made under conditions sufficient to provide that thereaction product contains less than one equivalent of an amino triazolegroup per molecule of reaction product, wherein the reaction product ischaracterized by an FTIR spectrum having a peak intensity in a region offrom about 1630 cm⁻¹ to about 1645 cm⁻¹ that ranges from about 5 toabout 45% of peak intensities of other peaks in a region of from about1500 cm⁻¹ to about 1800 cm⁻¹.
 8. The method of claim 7, wherein the fuelinjected diesel engine is a direct fuel injected diesel engine.
 9. Themethod of claim 7, wherein a molar ratio of (a) to (b) in the reactionproduct ranges from about 1:0.5 to about 1:1.5.
 10. The method of claim7, wherein the salt deposits are selected from the group consisting oftransition metal, alkali metal and alkaline earth metal carboxylatesfrom the internal components of the fuel injector.
 11. The method ofclaim 7, wherein the fuel is an ultra low sulfur diesel fuel.
 12. Amethod for preventing plugging of a fuel filter for fuel injectors of afuel injected diesel engine comprising operating the engine on a majoramount of fuel comprising from about 20 mg to about 120 mg per Kg offuel of a reaction product derived from (a) a polyisobutenyl substituteddicarboxylic acid, anhydride, or ester, wherein the polyisobutenyl grouphas a number average molecular weight ranging from about 200 to about3000 daltons and (b) an amine compound or salt thereof of the formula

wherein R is selected from the group consisting of hydrogen and ahydrocarbyl group containing from about 1 to about 15 carbon atoms, andR¹ is selected from the group consisting of hydrogen and a hydrocarbylgroup containing from about 1 to about 20 carbon atoms, wherein thereaction product is characterized by an FTIR spectrum having a peakintensity in a region of from about 1630 cm⁻¹ to about 1645 cm⁻¹ thatranges from about 5 to about 45% of peak intensities of other peaks in aregion of from about 1500 cm⁻¹ to about 1800 cm⁻¹, and wherein thereaction product is made under conditions sufficient to provide that thereaction product contains less than one equivalent of an amino triazolegroup per molecule of reaction product.
 13. The method of claim 12,wherein the fuel filter has 2 micron openings therein for fuel flow. 14.The method of claim 12, wherein the fuel comprises an ultra low sulfurdiesel (ULSD) fuel.
 15. The method of claim 12, wherein the reactionproduct is effective to prevent plugging of the fuel filter with saltdeposits selected from the group consisting of transition metal, alkalimetal and alkaline earth metal carboxylates from the internal componentsof the fuel injector.